1. Cross Reference to Related Applications
This application is related to commonly assigned U.S. patent application Ser. No. 629,860 filed Jul., 11, 1984.
2. Field of the Invention
This invention relates generally to improved simulation decoys useful in radar- and infrared-detection environments. More specifically, the invention relates to military defensive countermeasure systems, having utility as decoys for aircraft, ships, tanks, and other military targets under battlefield or warfare conditions.
3. Description of the Prior Art
In the practice of modern warfare, a variety of missiles have come into use which employ sensing means, such as radar and/or infrared detection means to determine the position and structure of potential targets, e.g., land-based vehicles, ships, and aircraft. Examples of such missiles include the "Sidewinder" heat-seeking missile, employed in air-to-air combat and the more recently developed French Exocet missile, which is radar-guided. The Exocet missile was used successfully in the Falklands war between Argentina and Great Britain as an anti-ship missile.
With regard to infrared-sensing devices employed in such missiles, it has been common practice to employ various decoy means, which burn or otherwise emit infrared radiation in use, such means being launched or otherwise deployed to provide a positional and structural perception by the detection means of an intended target. Such decoys provide means for aircraft, land-based vehicles or ships to elude the infrared-guided weapons.
Decoy systems of the aforementioned type are disclosed in U.S. Pat. No. 4,222,306 (a multiple decoy launching unit), U.S. Pat. No. 4,307,665 (same), U.S. Pat. No. 4,171,669 (a decoy flare cartridge containing a charge of jelled hydrocarbon fuel), French Patent No. 2,490,333 (a projectile containing explosives, such as material producing a flare or an infrared decoy), and U.S. Pat. No. 4,069,762 (an emissive decoy comprising an ignitable pyrotechnic composition, the ignition of which forms a cloud of droplets of aerosol from a liquid aerosol in a separate compartment of the decoy). Great Britain Patent No. 2,121,148 discloses a guided missile radar decoy comprising a metal-coated balloon which is inflated by compressed air, it being taught that several such balloons coupled together produce a reflection similar to that of a ship. Specifically, the balloons may be set up in "V" configuration to simulate a ship and thereby decoy radar-guided missiles.
A particular problem with infrared decoys of the prior art (e.g., parachute or projectile flares) is that modern infrared detection means have become sufficiently accurate insofar as their resolution characteristics are concerned to differentiate true targets from these previously effective decoys. Such infrared detection means as currently employed can differentiate a 1% change in temperature and thus can accurately resolve and differentiate such decoy means from the temperature and size profile of the actual target--a jet engine or missile exhaust, or a tank and its occupants. True and accurate thermal profiles of the actual target can be programmed in the control apparatus of the missile such that its infrared detection means "look" for the programmed thermal structure, e.g., of an engine block and cooling system network in a tank and thus are not confused by conventional infrared decoy displays.
In response thereto, the invention embodied in above-mentioned U.S. Ser. No. 629,860 was developed. This decoy comprises combustible carbon to provide the decoy with an infrared signature and a means of initiating the ignition of the carbon. Optionally, the decoy comprises metal-coated fibers to further provide an enhanced radar signature to the decoy. However, metal-coated fibers are subject to accelerated degradation at high temperatures. Incorporation of metal-coated fibers into the decoy therefore limited the temperature at which the decoy could be operated without loss of its structural integrity and/or enhanced radar signature.
Accordingly, there is a continuing need in the field of military countermeasures for a simulation decoy which can accurately mimic the thermal structure of an intended target and thus foil the aforementioned high resolution infrared detection means. In addition, because such infrared detection means are frequently coupled with radar detection means or used as an adjunct to an initial radar sighting which then is subjected to IR scanning to determine the precise nature of the radar detection, there is likewise a need for an improved infrared decoy of the aforementioned type which likewise accurately simulates the radar signature of an intended target. However, such objectives should be able to be accomplished at highly elevated temperatures while avoiding compromising the structure of the decoy and therefore its radar capabilities as well as the full infrared capabilities of the decoy.
It therefore is an object of the present invention to provide an improved simulation decoy whose position and structural purport (i.e., what the structure appears to be) are determinable by infrared detection means in combination with infrared detection means.